Hybrid Automatic Repeat reQuest (HARQ) is a mechanism to compensate the degradation of the received bit error ratio (BER) and frame error ration (FER) which results from fast fading and shadowing. Currently, two modes of HARQ are prevailing in IEEE 802.16e, 3GPP high speed packet access (HSPA) and 3GPP long-term evolution (LTE), i.e. chase combining and incremental redundancy (IR).
HARQ is a mature technology and widely implemented in traditional single-hop networks, such as 3GPP HSDPA/HSUPA. But in mobile multi-hop relaying networks, with introduction of relay stations (RS) into wireless network, new issues come out along with change of network topology structure. Firstly, from the perspective of propagation, distinct wireless environments potentially result in great differences in the HARQ retransmission performances within multiple hops, which would cause incompatibility of the transmission rates of different hops, and as a result the throughput of the relay terminal is sure to decrease. Secondly, the physical layer resources can be drained due to the assignment for both accessing and relaying. Thirdly, extra delay may be caused by HARQ retransmissions within multiple hops, especially in the systems differentiating terminals with time-slots in a frame. Thus, the above problems need to be considered in the HARQ retransmission procedure designed for a mobile multi-hop relaying network, and a corresponding mechanism should be employed to avoid occurrence of problems or at least lower the occurrence probability of system performance degradation potentially caused by such problems.
On the other side, it is generally believed that relay stations (RS) are limited in processing intelligence and shall have relatively simpler structures and lower costs. Thus, functions and the related complexity of relay stations (RS) should be taken into account when designing HARQ retransmission procedure for a mobile multi-hop relaying network.
Currently, there is no HARQ mechanism suitable for a mobile multi-hop relaying network in the prior art. To improve the technical solution for a mobile multi-hop relaying network, it is urgent to provide a method and corresponding device for HARQ dedicated for a mobile multi-hop relaying network and taking the special issues of the above mobile multi-hop relaying network into account.